I. Field of the Invention
The invention relates to humidifier systems which utilize an electrode boiler to generate steam by passing current through and between boiler electrodes submerged in water, and more particularly, to automatic controls for such humidifier systems for regulating the level of water in the boiler in conjunction with regulating the magnitude of the electrode current used for steam generation.
II. Description of the Prior Art
Prior humidifier systems including typical automatic controls are disclosed in Dall, U.S. Pat. No. 3,761,679, issued Sept. 25, 1973, Eaton Williams, U.S. Pat. No. 3,780,261, issued Dec. 18, 1973, and Eaton Williams, British Pat. No. 1,139,911.
This invention is concerned with this general area and has among its general objects to provide an automatic control for a humidifier system which utilizes digital logic circuitry and which includes improved modes of operation and other features not available in the prior art.
More particularly, this invention has among its principal objects to provide an electronic steam humidifier control which utilizes digital logic circuitry to regulate the boiler water level and magnitude of electrode current in accordance with a normally repetitive fill, boil, fill-on-drain cycle.
Another of the principal objects of the invention is to provide such a control incorporated in a humidifier system which can be utilized efficiently with local tap water having broad ranges of conductivities, the control automatically enriching the local tap water to a predetermined higher conductivity suitable for efficient boiler operation before the normally repetitive cycling occurs.
Another of the objects of the invention is to provide such a control which includes an abnormal operation indicator and high and low current indicators to inform the operator of the status or stage of operation of the electrode boiler and the control.
Another object of the invention is to provide such a humidifier control including digital logic circuitry which provides reliable and efficient control over the operation of the humidifier system, the control including a comparator network which provides a plurality of digital outputs having high or low states dependent upon the magnitude of electrode current.